Enterotoxigenic Escherichia coli (ETEC) is a type of Escherichia coli and the leading bacterial cause of diarrhea in the developing world, as well as the most common cause of traveler's diarrhea. A number of pathogenic isolates are termed ETEC, but the main hallmarks of this type of bacteria are expression of one or more enterotoxins and presence of fimbriae used for attachment to host intestinal cells.
LT is similar to cholera toxin; it increases the level of cAMP in intestinal cells, and this causes an increase in electrolyte and water excretion (diarrhea).
ST stimulates production of cGMP, also leading to increased fluid excretion and diarrhea.
Because enterotoxic E. coli strains are non-invasive, they do not cause inflammation. Infection with ETEC can cause profuse watery diarrhea with no blood nor leukocytes and abdominal cramping. Fever, nausea with or without vomiting, chills, loss of appetite, headache, muscle aches and bloating can also occur but are less common.